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Journal of Biomechanics

Chen Yang, Jason Bouffard, Divya Srinivasan, Shaheen Ghayourmanesh, Hiram Cantú, Mickaël Begon, Julie N Côté
Changes in neuromuscular strategies employed with fatigue during multi-joint movements are still poorly understood. Studies have shown that motor variability of individual joints increases when performing upper limb tasks to fatigue, while movement parameters related to the task goal remain constant. However, how the inter-limb coordination and its variability change during specific movement phases with fatigue is still unclear. The aim of this study was to assess the effects of neck-shoulder fatigue on shoulder and elbow kinematic variabilities, shoulder-elbow coordination and its variability, and endpoint characteristics during different phases of a forward pointing movement...
June 13, 2018: Journal of Biomechanics
Sarah A F Taylor, Angela E Kedgley, Alexander Humphries, Aliah F Shaheen
Kinematic assessments of the upper limb during activities of daily living (ADLs) are used as an objective measure of upper limb function. The implementation of ADLs varies between studies; whilst some make use of props and define a functional target, others use simplified tasks to simulate the movements in ADLs. Simulated tasks have been used as an attempt to reduce the large movement variability associated with the upper limb. However, it is not known whether simulated tasks replicate the movements required to complete ADLs or reduce movement variability...
June 9, 2018: Journal of Biomechanics
Junchao Guo, Xiaoyu Liu, Xili Ding, Lizhen Wang, Yubo Fan
Plantar fascia (PF) is a heterogeneous thickness structure across plantar foot. It is important significance to investigate the biomechanical behavior of the medial, middle and lateral PF regions. To investigate the non-uniform macro/micro structures of the different PF regions, the uniaxial tensile test of PF strips were performed to assess the mechanical behavior of PF. A scanning electron microscope (SEM) was used to visualize and measure the micro morphology of PF associated with collagen fibers. A three-dimensional foot finite element (FE) model was developed to quantify the tensile behavior of the internal PF...
June 8, 2018: Journal of Biomechanics
Shanette A Go, William J Litchy, Loribeth Q Evertz, Kenton R Kaufman
INTRODUCTION: Intramuscular pressure (IMP) is the fluid pressure generated within skeletal muscle and directly reflects individual muscle tension. The purpose of this study was to assess the development of force, IMP, and electromyography (EMG) in the tibialis anterior (TA) muscle during ramped isometric contractions and evaluate electromechanical delay (EMD). METHODS: Force, EMG, and IMP were simultaneously measured during ramped isometric contractions in eight young, healthy human subjects...
June 8, 2018: Journal of Biomechanics
Utku Gülan, Christelle Calen, Firat Duru, Markus Holzner
An aortic aneurysm is defined as a balloon-shaped bulging of all three histologic components of the aortic vessel walls (intima, media and adventitia). This dilation results from vessel weakening owing to remodeling, i.e. due to cystic degeneration of the Tunica media (Marfan), progression of atherosclerosis or presence of a bicuspid aortic valve. The growth rate of the aortic diameter varies from patient to patient and may progress until the aneurysm ultimately ruptures. The role of hemodynamics, i.e. blood flow patterns, and shear stresses that are supposed to intensify during aneurysm growth are not yet fully understood, but thought to play a key role in the enlargement process...
June 8, 2018: Journal of Biomechanics
Sorin Siegler, Tobias Konow, Claudio Belvedere, Andrea Ensini, Rewati Kulkarni, Alberto Leardini
Joint surface interaction and ligament constraints determine the kinematic characteristics of the ankle and subtalar joints. Joint surface interaction is characterized by joint contact mechanics and by relative joint surface position potentially characterized by distance mapping. While ankle contact mechanics was investigated, limited information is available on joint distance mapping and its changes during motion. The purpose of this study was to use image-based distance mapping to quantify this interaction at the ankle and subtalar joints during tri-planar rotations of the ankle complex...
June 7, 2018: Journal of Biomechanics
Erik Chumacero, James Yang, James R Chagdes
To achieve human upright posture (UP) and avoid falls, the central nervous system processes visual, vestibular, and proprioceptive information to activate the appropriate muscles to accelerate or decelerate the body's center of mass. In this process, sensory-motor (SM) latencies and muscular deficits, even in healthy older adults, may cause falls. This condition is worse for people with chronic neuromuscular deficits (stroke survivors, patients with multiple sclerosis or Parkinson's disease). One therapeutic approach is to recover or improve quiet UP by utilizing a balance board (BB) (a rotating surface with a tunable stiffness and time delay), where a patient attempts to maintain UP while task difficulty is manipulated...
May 31, 2018: Journal of Biomechanics
Sarah E Miller, Ava D Segal, Glenn K Klute, Richard R Neptune
Lower-limb amputees have a higher risk of falling compared to non-amputees. Proper regulation of whole-body angular momentum is necessary to prevent falls, particularly in the frontal plane where individuals are most unstable. However, the balance recovery mechanisms used by lower-limb amputees when recovering from a perturbation are not well-understood. This study sought to understand the balance recovery mechanisms used by lower-limb amputees in response to mediolateral foot perturbations by examining changes to frontal plane whole-body angular momentum and hip joint work...
May 23, 2018: Journal of Biomechanics
Joshua R Jarrell, Brad J Farrell, Robert S Kistenberg, John F Dalton, Mark Pitkin, Boris I Prilutsky
Ongoing animal preclinical studies on transcutaneous bone-anchored prostheses have aimed to improve biomechanics of prosthetic locomotion in people with limb loss. It is much less common to translate successful developments in human biomechanics and prosthetic research to veterinary medicine to treat animals with limb loss. Current standard of care in veterinary medicine is amputation of the whole limb if a distal segment cannot be salvaged. Bone-anchored transcutaneous prostheses, developed for people with limb loss, could be beneficial for veterinary practice...
May 23, 2018: Journal of Biomechanics
Céline Schreiber, Stéphane Armand, Florent Moissenet
The pathology's impact on gait pattern may be overestimated by conventional gait indices (Gillette Gait Index - GGI, Gait Deviation Index - GDI, Gait Profile Score - GPS), since impairments' consequences on kinematics may be amplified by a change in walking speed. The objectives of this study were to evaluate the influence of walking speed on the computation of gait indices and to propose a corrective method to cancel the effects of walking speed. Spatiotemporal parameters and kinematics of fifty-four asymptomatic participants (30 M/24 W, 37...
May 23, 2018: Journal of Biomechanics
Alexander Jung, Wolfram Müller, Manfred Staat
Wind is closely associated with the discussion of fairness in ski jumping. To counter-act its influence on the jump length, the International Ski Federation (FIS) has introduced a wind compensation approach. We applied three differently accurate computer models of the flight phase with wind (M1, M2, and M3) to study the jump length effects of various wind scenarios. The previously used model M1 is accurate for wind blowing in direction of the flight path, but inaccuracies are to be expected for wind directions deviating from the tangent to the flight path...
May 23, 2018: Journal of Biomechanics
Dong Liu, Guo-Yang Li, Chen Su, Yang Zheng, Yu-Xuan Jiang, Lin-Xue Qian, Yanping Cao
It has been reported that ex vivo viscoelastic properties of liver tissues usually differ from those measured in in vivo state due to the reasons such as the effects of perfusion, temperature, and native pre-stress. Therefore, the development of an appropriate ex vivo protocol, which enables the measurement of liver mechanical properties close to those in vivo, is of great importance and has been pursued over the years. In this paper, we propose a simple protocol by ligating the liver when performing ex vivo indentation relaxation tests...
May 22, 2018: Journal of Biomechanics
Xu Huang, Donghui Liu, Xiaoping Yin, Yajun E, Zhiqiang Li, Wenchang Tan, Yunlong Huo
Posterior communicating artery (PCoA) aneurysms frequently rupture in small size (<7 mm). The aim of the study is to demonstrate morphometric and hemodynamic analyses in ruptured and unruptured PCoA aneurysms to improve predictive accuracy for rupture. Geometrical models were reconstructed from rotational DSA images of 57 ruptured and 22 unruptured side-wall PCoA aneurysms, which were classified into four two-dimensional (2D) groups by a combination of H/D and H/S ratios (H: dome height, D: dome diameter, and S: semi-axis height)...
May 22, 2018: Journal of Biomechanics
Mostafa Abbasi, Dong Qiu, Yashar Behnam, Danny Dvir, Chadd Clary, Ali N Azadani
Transcatheter aortic valve replacement (TAVR) is a safe and effective treatment option for patients deemed at high and intermediate risk for surgical aortic valve replacement. Similar to surgical aortic valves (SAVs), transcatheter aortic valves (TAVs) undergo calcification and mechanical wear over time. However, to date, there have been limited publications on the long-term durability of TAV devices. To assess longevity and mechanical strength of TAVs in comparison to surgical bioprosthetic valves, three-dimensional deformation analysis and strain measurement of the leaflets become an inevitable part of the evaluation...
May 22, 2018: Journal of Biomechanics
Jennie M Scarvell, Catherine R Galvin, Diana M Perriman, Joseph T Lynch, Robert W M van Deursen
BACKGROUND: While several studies describe kinematics of healthy and osteoarthritic knees using the accurate imaging and computer modelling now possible, no systematic review exists to synthesise these data. METHOD: A systematic review extracted quantitative observational, quasi-experimental and experimental studies from PubMed, Scopus, Medline and Web of Science that examined motion of the bony or articular surfaces of the tibiofemoral joint during any functional activity...
May 21, 2018: Journal of Biomechanics
Julian C Acasio, Courtney M Butowicz, Pawel R Golyski, Maury A Nussbaum, Brad D Hendershot
Trunk postural control (TPC) has been investigated in several populations and tasks. Previous work observed targeted training of TPC via isolated trunk control tasks may improve performance in other activities (e.g., walking). However, the nature of this relationship remains unknown. We therefore investigated the relationship between TPC, at both the global (i.e., response to finite perturbations) and local (i.e., resistance to continuous perturbations) levels, during walking and unstable sitting, both at varying levels of task demand...
May 21, 2018: Journal of Biomechanics
Yawei Wang, Hongdai Sun, Jianan Wei, Xuesong Liu, Tianya Liu, Yubo Fan
Incorporating the intrinsic variability of heart contractility varying with heart rate into the mathematical model of human heart would be useful for addressing the dynamical behaviors of human cardiovascular system, but models with such features were rarely reported. This study focused on the development and evaluation of a mathematical model of the whole heart, including the effects of heart contractility varying with heart rate changes. This model was developed based on a paradigm and model presented by Ottesen and Densielsen, which was used to model ventricular contraction...
May 19, 2018: Journal of Biomechanics
Sandra K Hnat, Ben J H van Basten, Antonie J van den Bogert
Force plates for human movement analysis provide accurate measurements when mounted rigidly on an inertial reference frame. Large measurement errors occur, however, when the force plate is accelerated, or tilted relative to gravity. This prohibits the use of force plates in human perturbation studies with controlled surface movements, or in conditions where the foundation is moving or not sufficiently rigid. Here we present a linear model to predict the inertial and gravitational artifacts using accelerometer signals...
May 19, 2018: Journal of Biomechanics
Jennifer R Yong, Amy Silder, Kate L Montgomery, Michael Fredericson, Scott L Delp
Tibial stress fractures are a common and debilitating injury that occur in distance runners. Runners may be able to decrease tibial stress fracture risk by adopting a running pattern that reduces biomechanical parameters associated with a history of tibial stress fracture. The purpose of this study was to test the hypothesis that converting to a forefoot striking pattern or increasing cadence without focusing on changing foot strike type would reduce injury risk parameters in recreational runners. Running kinematics, ground reaction forces and tibial accelerations were recorded from seventeen healthy, habitual rearfoot striking runners while running in their natural running pattern and after two acute retraining conditions: (1) converting to forefoot striking without focusing on cadence and (2) increasing cadence without focusing on foot strike...
May 18, 2018: Journal of Biomechanics
Hao Yang Chan, Peter S Walker
The design of a total knee replacement implant needs to take account the complex surfaces of the knee which it is replacing. Ensuring design performance of the implant requires in vitro testing of the implant. A considerable amount of time is required to produce components and evaluate them inside an experimental setting. Numerous adjustments in the design of an implant and testing each individual design can be time consuming and expensive. Our solution is to use the OpenSim simulation software to rapidly test multiple design configurations of implants...
May 18, 2018: Journal of Biomechanics
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